Density of States

There is a lot of useful information about local bonding that can be extracted by using paw_dos that is worth taking a look at now. We can plot the total density of states, the contribution to the COOP of a combination of particular atoms or orbitals, or both.

1.

Read section 12 in the Manual to get an idea of the theoretical basis for the PAW density of states tool.

2.

Create an h2co.dcntl file, which will tell the paw_dos program what to do:

• The structure of this file is similar to that of the .cntl file.
• We set the location of input and output files. One can also output to the stdout for piping to xmgr and the like. Let's analyze the total dos, and output to a file h2co.total_dos_out
• We tell it what we want to analyze, with !WEIGHT for diagonal elements of the PDOS operator or !COOP for the off-diagonal ones. Each of these can be referenced with a NAME so we can direct the output of each individually.
• Copy the setup from Figure 10 to your h2co.dcntl file.

  

Figure: h2co.dcntl (1)

  

Figure: h2co.dcntl (2)

3.

Create the plotable data: paw_dos h2co.dcntl

alpha:~/tutorial/h2co> paw_dos h2co.dcntl

4.

Plot the data with xmgr (using $X_1, Y_1, Y_2, \cdots$ format) to see the total density of states plot (you should probably autoscale, too, if this is not the default). The default has no gaussian witdth expansion, so we probably see just a bunch of lines at the state occupations.

alpha:~/tutorial/h2co> xmgr -nxy h2co.total_dos_out

5.

Add in grid information into your h2co.dcntl file to get a nicer plot (See Figure 11 for the changes).